1. Field
The present disclosure relates to a gas separation membrane with a ladder-structured polysilsesquioxane and a method for fabricating the same. More particularly, it relates to a gas separation membrane using a ladder-structured polysilsesquioxane with superior gas separation property or a composite thereof, gas selectivity and permeability of which can be selectively controlled by the crosslinking properties of the ladder-structured polysilsesquioxane, their organic functional groups, or the combination of both, and a method for fabricating the same.
[Description about National Research and Development Support]
This study was supported by the Korea CCS R&D Center (KCRC) (No. 2014M1A8A1049315) and Korea Institute of Energy Technology Evaluation and Planning (KETEP) (No. 20135010100750).
2. Description of the Related Art
The recent researches on new polymer materials are advancing toward functionalization to improve thermal, mechanical and electrical properties. In particular, organic-inorganic hybrid materials are drawing attentions. The most important things in the fabrication of organic-inorganic hybrid materials are compatibility between the organic polymer and inorganic sieves and stability without thermal degradation. As a material satisfying these requirements, highly heat-resistant polysilsesquioxane (PSSQ) is in the limelight (D. Kessler and P. Theato, Macromolecules 2008, 41, 5237-5244).
PSSQ is widely used in heat-resistant materials, weather-resistant materials, impact-resistant materials, packaging materials, encapsulation materials, insulating materials, lubricants, release agents, semi-gas-permeable coating materials, flexible substrates, etc. in the form of oil, rubber, resin, etc. and is recognized as a very important polymer in various industries.
Meanwhile, a gas separation process of separating a specific gas using a gas separation membrane is drawing a lot of attentions as the future energy technology with excellent energy efficiency and is also known as an environment-friendly technology.
The gas separation membrane used in the gas separation process is typically fabricated from an easily processable polymer such as cellulose acetate, polysulfone and polyimide. The gas separation membrane separates gases based on the solution-diffusion mechanism. That is to say, gas molecules are dissolved in the separation membrane at high pressure (solution), which diffuse through polymer chains (diffusion) and then are desorbed from the lower-pressure side of the gas separation membrane (desorption). The ‘solution (sorption)’ which is a thermodynamic factor, predominates as the critical temperature of the gas molecules is higher, whereas the kinetic factor ‘diffusion’ predominates as the size of the gas molecules is smaller.
However, although the above-described polymers used as the material of the gas separation membrane can be easily processed into a separation membrane, their separation performance should be improved for the commercialization. The separation performance of ladder-structured polysilsesquioxane-based membranes can be improved simply by engineering various organic functional groups with thermal/light-induced crosslinking.